Worth is relative to different people. What sort of music do you listen to?
While the UE900 will handle most of the things you can throw at it, if you have specific music preferences there are cheaper IEMs that would cater to you better.

Mainly i used to listen pretty much everything from Rock, Pop, RnB etc.. (excluding electronic music like Tecno, House, Dubstep and all that kind of genre)

Ok the UE900 has very neutral (amazingly punchy) bass after the mini-bore has been filled. It has slightly forward and clear mids, and the treble is well extended but does not have amazing presence. If you are a treblehead I would recommend the TF10.

I have the UE 700 from the "first stock". The second stock has diffent tips, and maybe they changed something in the sound signature to.

Mine UE 700 has high quality mids and highs. They are forward in the music. It sounds cristal clear and has excellent instrument separation and detail. The lows are not big in quantity, but I think they have good quality if the seal is right. I listen to trance music, and I think the bass is just right. I use non-stock tips.

I have the UE 700 from the "first stock". The second stock has diffent tips, and maybe they changed something in the sound signature to.

Mine UE 700 has high quality mids and highs. They are forward in the music. It sounds cristal clear and has excellent instrument separation and detail. The lows are not big in quantity, but I think they have good quality if the seal is right. I listen to trance music, and I think the bass is just right. I use non-stock tips.

Mine works great, but I heard about cable problems.

I had a pair from the first stock, which I had to get replaced via warranty (which they were super cool about, btw) and they sent me a pair from the second batch. It comes with two sets of Complys.

Seconded about the mids and highs. Smooth and detailed. Highs are very crisp, bordering on the bright side. The bass can be a little lacking at first but it seems to come in nicely after some burn-in. I have the bass boost turned on with my E10 and they get low and handle everything quite nicely.

Hey. A bit late but do consider the Rockit R-50. With maybe foam tips to kill of the sibilance. Great detail, soundstage. Strong bass with good sub bass, extended treble but with sibilance. Mids are neutral. Very good price/performance. But take some time with tips.